Naturally occurring in the skin, Hyaluronic Acid (HA) acts as a built-in hydrator, holding in moisture to keep skin healthy. Over the years, the level of HA in your skin decreases, reducing your skin’s ability to rehydrate efficiently—which can lead to wrinkles and lines. Using a mix of five forms of HA, the HA5 Rejuvenating Hydrator by Skinmedica improves your skin’s ability to replenish its own HA and immediately smoothes dryness.